556 research outputs found
Management Choices: Native, Interseeded Native, or Tame Pastures
The objective of the 3-year grazing study was reported in this bulletin was to develop effective, economical, and sustained beef cattle production on native and tame pastures with and without energy supplementation. The three pasture systems studied were native range, interseeded native range, and a tame pasture series
Dry Matter and Nutrient Losses for Large Round Hay Bales Stored Outside
Large round bales have become a commonly used means for packaging hay. Some questions still remain, however, concerning the best techniques for handling, storing and feeding these packages. In this study, three different arrangements of bales were used to compare storage characteristics over a 1-year period
Pasture Systems: Economic Alternatives
Insufficient income to provide a satisfactory standard of family living is not uncommon among farmers and ranchers in South Dakota. The high cost of land rules out expansion for many. Consequently, they must look for ways to enhance income with their existing resources. For some, more intensive pasture management is an opportunity to increase income from their beef cow operations. This bulletin (1) investigates the economic feasibility of several pasture improvement systems and (2) estimates the impact of various productivity levels on returns to labor and management
Travois: An Alfalfa for Grazing
In 1948, M. W. Adams and G. Semeniuk recognized the economic potential of introducing alfalfa into ranges and pastures of the more arid parts of South Dakota. They initiated a breeding program directed toward developing very hardy, disease resistant alfalfas which would persist indefinitely when grazed by livestock. Travois is an outgrowth of that program and is believed to meet these requirements
Coagulation and fragmentation processes with evolving size and shape profiles : a semigroup approach
We investigate a class of bivariate coagulation-fragmentation equations. These equations describe the evolution of a system of particles that are characterised not only by a discrete size variable but also by a shape variable which can be either discrete or continuous. Existence and uniqueness of strong solutions to the associated abstract Cauchy problems are established by using the theory of substochastic semigroups of operators
Intervención del edificio de arte y cultura en el ITESO (puente)
La intervención realizada tiene como finalidad reivindicar la madera como un material constructivo pertinente para la edificación. Situación que en México se ha visto limitada por diferentes factores como lo son la sobredimensión de los elementos en reglamentos, la casi inexistente regulación del material y el paradigma de su deficiente seguridad y durabilidad comparada con otros materiales como lo son el acero y el concreto. Los beneficios de este material trascienden sus limitantes, siendo un material sustentable, la madera podría reducir en mayor o menor medida el abuso de materiales contaminantes en la construcción, además México cuenta con un gran abasto de maderas de primera calidad y rápido crecimiento.
El acercamiento consistió en diseñar en madera un puente ya propuesto en concreto, para esto se consideró proponer armaduras de madera, se enfocó en darle solución a varios elementos estructurales que además de estéticos, funcionaran adecuadamente como un puente y tenga el potencial de ser un producto fácilmente transportable y auto construible
Borderline Aggregation Kinetics in ``Dry'' and ``Wet'' Environments
We investigate the kinetics of constant-kernel aggregation which is augmented
by either: (a) evaporation of monomers from finite-mass clusters, or (b)
continuous cluster growth -- \ie, condensation. The rate equations for these
two processes are analyzed using both exact and asymptotic methods. In
aggregation-evaporation, if the evaporation is mass conserving, \ie, the
monomers which evaporate remain in the system and continue to be reactive, the
competition between evaporation and aggregation leads to several asymptotic
outcomes. For weak evaporation, the kinetics is similar to that of aggregation
with no evaporation, while equilibrium is quickly reached in the opposite case.
At a critical evaporation rate, the cluster mass distribution decays as
, where is the mass, while the typical cluster mass grows with
time as . In aggregation-condensation, we consider the process with a
growth rate for clusters of mass , , which is: (i) independent of ,
(ii) proportional to , and (iii) proportional to , with . In
the first case, the mass distribution attains a conventional scaling form, but
with the typical cluster mass growing as . When , the
typical mass grows exponentially in time, while the mass distribution again
scales. In the intermediate case of , scaling generally
applies, with the typical mass growing as . We also give an
exact solution for the linear growth model, , in one dimension.Comment: plain TeX, 17 pages, no figures, macro file prepende
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Pan-active imidazolopiperazine antimalarials target the Plasmodium falciparum intracellular secretory pathway.
A promising new compound class for treating human malaria is the imidazolopiperazines (IZP) class. IZP compounds KAF156 (Ganaplacide) and GNF179 are effective against Plasmodium symptomatic asexual blood-stage infections, and are able to prevent transmission and block infection in animal models. But despite the identification of resistance mechanisms in P. falciparum, the mode of action of IZPs remains unknown. To investigate, we here combine in vitro evolution and genome analysis in Saccharomyces cerevisiae with molecular, metabolomic, and chemogenomic methods in P. falciparum. Our findings reveal that IZP-resistant S. cerevisiae clones carry mutations in genes involved in Endoplasmic Reticulum (ER)-based lipid homeostasis and autophagy. In Plasmodium, IZPs inhibit protein trafficking, block the establishment of new permeation pathways, and cause ER expansion. Our data highlight a mechanism for blocking parasite development that is distinct from those of standard compounds used to treat malaria, and demonstrate the potential of IZPs for studying ER-dependent protein processing
The regulatory subunit of PKA-I remains partially structured and undergoes β-aggregation upon thermal denaturation
Background: The regulatory subunit (R) of cAMP-dependent protein kinase (PKA) is a modular flexible protein that responds with large conformational changes to the binding of the effector cAMP. Considering its highly dynamic nature, the protein is rather stable. We studied the thermal denaturation of full-length RIα and a truncated RIα(92-381) that contains the tandem cyclic nucleotide binding (CNB) domains A and B. Methodology/Principal Findings: As revealed by circular dichroism (CD) and differential scanning calorimetry, both RIα proteins contain significant residual structure in the heat-denatured state. As evidenced by CD, the predominantly α-helical spectrum at 25°C with double negative peaks at 209 and 222 nm changes to a spectrum with a single negative peak at 212-216 nm, characteristic of β-structure. A similar α→β transition occurs at higher temperature in the presence of cAMP. Thioflavin T fluorescence and atomic force microscopy studies support the notion that the structural transition is associated with cross-β-intermolecular aggregation and formation of non-fibrillar oligomers. Conclusions/Significance: Thermal denaturation of RIα leads to partial loss of native packing with exposure of aggregation-prone motifs, such as the B' helices in the phosphate-binding cassettes of both CNB domains. The topology of the β-sandwiches in these domains favors inter-molecular β-aggregation, which is suppressed in the ligand-bound states of RIα under physiological conditions. Moreover, our results reveal that the CNB domains persist as structural cores through heat-denaturation. © 2011 Dao et al
X-ray and IR Point Source Identification and Characteristics in the Embedded, Massive Star-Forming Region RCW 108
We report on the results of an approximately 90 ks Chandra observation of a
complex region that hosts multiple sites of recent and active star formation in
ARA OB1a. The field is centered on the embedded cluster RCW 108-IR and includes
and a large portion of the open cluster NGC 6193. We detect over 420 X-ray
sources in the field and combined these data with deep near-IR, Spitzer/IRAC
and MSX mid-IR data. We find about 360 of the X-ray sources have near--IR
counterparts. We divide the region into 5 parts based on the X-ray point source
characteristics and extended 8 micron emission. The most clearly defined
regions are the central region - identified by embedded sources with high
luminosities in the both the near-IR and X-ray as well as high X-ray
temperatures (about 3 keV) and the eastern region - identified by low
extinction and 1 keV X-ray temperatures. Other regions, identified by their
directional relationship to RCW 108-IR are less uniform - representing
combinations of the first two regions, independent star formation epochs, or
both. Over 18% percent of the cluster members with over 100 counts exhibit
flares. Overall about 50% of the stars appear to have optically thick disks
when IRAC data are employed. The largest fraction of X-ray sources are best
described as possessing some disk material via a more detailed extinction
fitting. We estimate that the total number of pre--main sequence stars in the
field is about 1600. Approximately 800 are confined to (1.1 pc) central region.Comment: 63 pages including 18 figures, and 15 tables. Tables 1,2,5,7,10,and
11 have been stubbed in the text and included as ancillary files. Accepted by
the Astronomical Journa
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